Hemofiltration (HDF) is a form of renal replacement therapy that utilizes convective in combination with diffusive clearance, which is used in standard hemodialysis. In online HDF, the substitution fluid is produced by the dialysis machine, which enables large convection volumes. Compared with standard hemodialysis, HDF removes more middle-molecular-weight solutes. Some, though not all, studies have suggested that HDF is associated with improved clinical outcomes, providing adequate convection volumes are achieved.